Expansible linkage



ne 1964 TETSUZO SHIBUYA 3,135,036

EXPANSIBLE LINKAGE Filed Dec. 28, 1961 Z'Sheet-Sheet 1 June 2, 1964TETSUZO SHIBUYA EXPANSIBLE LINKAGE 2 Sheets-Sheet 2 Filed Dec. 28, 1961United States Patent 3,135,086 EXPANSIBLE LINKAGE Tetsuzo Shibuya, 463-chon1e, Nakadori, Miyakojnna-ku,

Osaka, Japan Filed Dec. 28, 1961, Ser. No. 163,930 Claims priority,application Japan Feb. 13, 1961 1 Claim. (Cl. 59-79) This inventionrelates to improvements in the manufacture of expansible or extendablelinkage for use in articles of jewelry such as bracelets, bands, beltsand the like.

There are known pantagraph-shaped expansible linkages which comprise aplurality of pairs of links, each pair of links being pivotallyconnected to each other at their centers in superimposed relationship toform an X-shaped link unit and also pivotally connected to adjacentpairs of links of the same form and construction. The expansiblelinkages of this type are popular in the bracelets for wrist-watches.The linkage brackets with a certain number of pairs of links exertdifferent binding forces against the various wrists of persons who wearit. In order to make a watch-bracelet so as to have a com fortablebinding force for a wearer,it is necessary to control the length of thebracelet by adding or reducing the number of pairs of links composing alinkage. However, in the usual type of watch-bracelets, both ends ofeach pair of links are connected to the adjacent pairs of links byriveting so that aplurality of pairs of links may be locked securelyagainst disconnection in use. This makes it diflicult to take oif a pairor pairs of links from, or add links to the linkage of the bracket.

Some attempts have been made to connect the link ele- .ments withoutriveting or similar mechanical operations. For example, in theUnitedStates Patent No. 2,225,746, means for pivotally connecting'thelink-elements comprises openings at the ends of certain of thelink-elements and hooked prongs on cooperating link-elements and thehooked prongs on certain of the elements engage through the openings inother link-elements with the hooks adapted to overlie the sides of saidopenings to prevent disconnection of the link-elements. In this type oflinkages, however, after the parts of the linkage are once assembled thepivoted joints at the ends of the links cannot be released and it isvery diflicult to take oil a pair or some pairs of link-elements fromthe linkage to shorten its length as desired as well as the linkages ofwhich parts are connected by means of riveting.

The primary object of the present invention is to provide. linkages forarticles ofjewelry such as bracelets, bands, belts and the like in whichthe above disadvantages can be avoided.

Another object of the invention is to provide expansible linkagebracelets comprising a series of pairs of links which can be easilyconnected and disconnected to obtain linkages of any desirable length.

A particular object of the invention is to provide improved means forpivotally connecting the link-elements with" openings at the ends ofcertain of the link-elements and hooked prongs on cooperatinglink-elements, in which .thehooked prongs can easily engage the openingsin the operation for connecting link-elements to each other. A furtherobject of the invention is to provide jointmeans for connecting pairs oflinks at their extremities, whereby each pair of links can be connectedand disconnected only when they are put in such an unusual form ofexpansion and curvature as scarcely happens when they are in daily use.

A still further object of the invention is to provide the expansiblelinkages in which the shells whichcover the outside link-elements toembellish the completed arti lets.

cle and conceal its mechanical construction may be shaped and designedas desired.

Other objects of the present invention will be apparent from thefollowing disclosure of typical embodiments thereof, as set forth in theaccompanying drawings, wherein:

FIG. 1 is a plan view of a watch-bracelet embodying the presentinvention;

FIG. 2 is a greatly enlarged rear view, partly in section, of thepresent expansible linkage showing it contracted into closely adjacentrelationship;

FIG. 3 is a further enlarged sectional view taken on line 3-3 of FIG. 2and showing the central pivotal joint between the links and the springmeans for maintaining the linkage contracted in length;

FIG. 4 is a rear view on a greatly enlarged scale, partly in section, ofthe linkage with its parts extended;

FIG. 5 is a rear, perspective view of two pairs of linkelements inassembled relationship of the linkage illustrated in FIG. 2;

FIG. 6 is a further enlarged sectional view on line 6--6 of FIG. 4;

FIGS. 7 and 8 are detailed sectional views similar to FIG. 6 of jointmeans showing two different states, in which a pair of cooperating linksare bent in the direc tions, respectively indicated by the arrows;

FIG. 9 is a further enlarged sectional view of FIG. 6 illustrating thedimensional conditions of the .hooked prong and slot; 7

FIG. 10 a sectional view taken on line 1010 of FIG. 9;

FIG. 11 is a sectional view similar to FIG. 9 of another embodiment ofjoint means according to the invention; and

FIG. 12 is a plan view of the linkage which is connected to awrist-watch to form a complete ring.

The invention is adapted particularly for use in the manufacture offlexible bracelets, bands, and other expansible linkages of a type nowpopular in watch-brace- This type of linkage comprises a plurality ofarticulate members pivotally connected at their centers and alsopivotally joined at their extremities in X-relationship similar to theconstruction of the pantagraphs. The improved linkage may also consistof a plurality of elongated members of generally S-shape pivotallyconnected at their centers in superimposed relationship and with theiropposite ends also pivotally joined so that they may be contracted intoclose association as shown in FIGS; 1 and 2, or extended as indicated inFIGS, 4 and -5, by rocking them on their central pivots.

When embodied in articles of jewelry, the linkage is preferablyconstructed with the pivotally-connected linkelements enclosed insimilarly-shaped shells which may :be of precious metal or platedtherewith to embellish the completed article and conceal its mechanicalconstruction.

In the linkage construction illustrated in the drawings the mechanicalpivotal elements are constructed 'in complementary pairs in theform'shown in FIG. 5, being preferably stamped out from sheet-metal.FIG. 5 shows a rear, perspective view of two pairs of link-elements inassembled relationship. Each lower link element 11 consists preferablyof flat substantially S-shaped stamping having an elongated main portionwith relatively straight sides and oppositely curved ends.

The element 11 is punched or perforated the the center to provide arelatively large circular opening 13 as shown in FIG. 3, while at itsends are smaller openings 14. The openings 14 are preferably shaped inthe form of a slot as shown in the drawings. 1

The complementary upper link 12 which is pivoted centrally to the lowerlink 11 crosswise thereof is of the same general shape as the link 11,but adapted to be connected thereto in reverse underlying relationship.For this purpose the link 12 is provided at its center with anupstanding cylindrical flange forming a hollow rivet 15 adapted forinsertion through the central opening 13 in the lower link 11 with itsend riveted or swaged over the edge thereof, as shown in FIG. 3 so aspivotally to connect the two link-elements in overlying relationship.Each pair of link-elements 11 and 12 are assembled and pivotally joinedto adjacent pairs of link-elements of the same form and construction. Inthis manner a whole series of links are assembled in crossed andsuperimposed relationship with their ends pivotally joined to providefor extension of the linkage as a whole.

To cause the linkage to be maintained normally in contractedrelationship as shown in FIG. 1, a plurality of helical springs 18 areenclosed within the cylindrical flanges or hollow rivets 15 on theelements 12 with their opposite ends extending outwardly and bearingagainst the sides of the shells 19 and 20 which enclose the top andbottom of the joined link-elements 11 and 12. The upper end 21 of eachspring 18 extends outwardly in a straight arm with its end bearingagainst the side of the upper shell 20, while the lower arm 22 of thespring 18 is similarly directed against the side of the bottom shell 19;the springs being thus maintained under tension with their ends exertinga force against each upper and lower link-element and tending to swingthem on their central pivots to bring them into substantial alignment.

The invention relates particularly to the means for pivotally connectingthe outer ends of the link elements 11 and 12. For this purpose theupper link 12 is formed at its ends with downwardly projecting prongs orlugs 16 having outwardly directed lateral projection or hooks 17 attheir lower ends and the lower link 11 is provided at its ends withslots 14, the length of which is shorter than the lateral projections orhooks 17. Preferably, the prongs or lugs 16 are constructed integrallyof the links in the stamping operation, but they may be made separatetherefrom and suitably attached thereto.

The direction of the lateral projections or hooks 17 is aligned with thedirection of the length of the slots 14 when the linkage is greatlyextended to the utmost extent as shown in FIGS. 4 and 5. At thisposition the lateral projection or hook 17 is also aligned with the slot14 n the straight line in the direction of the length of the linkage asshown in FIG. 4.

The hooked prong 16 and slot 14 as joint means according to theinvention are preferably shaped under the following dimensionalconditions as illustrated in FIGS. 9 and 10: the length of the slot 14,a is smaller than b, the length of the lateral projection 17 of theprong 16 but larger than c, the diameter of the prong 16; the width ofthe slot 14, d is larger than c, the diameter of the prong 16; inaddition the diagonal width of the lateral projection 17 at its root, eis smaller than a, the length of the slot 14 but larger than d, thewidth of the slot 14.

So far as the above conditions are satisfied, both the shape anddimension of the prong and slot may be designed at will. For example,the prong may be shaped in its lateral section in any form of a circle,an ellipse, an egg-shape and a Wedge-shape and the shape of the slot maydepend on the sectional form of the prong. It is also possible to carryout the invention in such a manner as illustrated in FIG. 11 in whichthe hooked prong is substantially T-shaped and is provided with alateral portion extending in opposite directions outwardly and inwardly.The corresponding members and dimensions are indicated with the samereference numerals and symbols as in FIG. 9.

Each pair of link-elements 11 and 12 assembled in an X-s'haped link unitare joined at their ends to other pairs of links of similar constructionand arrangement by first extending the two pairs of connected elements11 and 12 until the projection or hook 17 and the slot 14 of one pairare aligned in the direction of the length of the link age with the slot14 and the projection or hook 17 of the other pair, respectively, andthen inserting the projections or hooks 17 into the respective slots 14through the state as shown in FIG. 7. The lugs 16 are thus positioned inthe slots 14 for pivotally connecting the ends of the links. A wholeseries of pairs of links are joined together in this manner to provide alinkage of any desired length.

The two pairs'of link-elements thus connected are also detachable fromeach other only when they are extremely extended as shown in FIGS. 4 and5, in which the lateral projection or hook 17 and the slot 14 of onepair are aligned with the slot 14 and the projection or hook 17 of theother pair in the direction of the length of the linkage. At any othercontracted or half extended positions in which the projection or hook 17and slot 14 of one pair are not aligned with the slot 14 and theprojection or hook 17 of the other pair, these two pairs oflink-elements can be neither connected to, nor disconnected from eachother because the hooked prong 16 is provided with an expanded portion,namely the diagonal diameter of the lateral projection 17 at its root inthe direction normal to the axis of the prong 16 is larger than thewidth of the slot. At the fully extended state as shown in FIGS. 4 and5, the adjoining two pairs of link-elements are not yet ready to detachfrom each other because each lateral projection or hook 17 is longerthan the length of the slot 14 and they are still in the state of aperfect engagement. Actual disconnection of the two pairs oflink-elements can be carried out by tilting one of the pairs ofconnected elements with respect to the other pair in the directionindicated by the arrow in FIG. 7. The lug 16 followed by the lateralprojection 17 then passes aslant through the slot 14 to be detached fromit. On the contrary, if a bending moment is given between the connectedelements in the opposite direction, that is, in the direction of thearrow shown in FIG. 8, the lateral projection 17 collides against thelower surface of the link-element 11 or the shell 19. When the linkageconstructed as above is used, for example, for a watch-bracelet, thelinkage is so connected to a wrist-watch to form a complete ring as toput the link-element 12 having the lugs 16 outside and the link-elements11 having slots 14 inside as shown in FIG. 12, whereby such a bendingmoment as shown in FIG. 7 scarcely happens in ordinary use.

The joint means according to the invention is advantageous in that theend of the lateral projection 17 can easily engage in the slot 14 in theoperation for connecting link-elements 11 and 12 to each other sinceboth the lateral projection 17 and slot 14 are visible, the lateralprojection being outwardly directed. In addition the linkage accordingto the invention has the advantage that the form of the shell 20 of theoutside link-element 12 may be designed more freely than in any otherlinkages of known type. For example the shell 20 may not only be shapedwith a gentle slope as shown in FIGS. 6 to 9 and 11 but also cover theoutside link-element 12 in directly and closely superimposedrelationship, because there is no projection on the upper surface of theoutside link-element 12.

While the device is herein shown asernbodied in a preferred form ofconstruction, it is to be understood that various modifications may bemade in the structure and arrangement of its parts without departingfrom the spirit or scope of the invention.

What I claim is:

In an expansible linkage for articles of jewelry such as bracelets,bands, belts and the like, the combination of a plurality of pairs oflink-elements, each pair of linkelements consisting of an outer and aninner link-element pivotally connected to each other at their centers insuperimposed relationship to form an X-shaped link unit, with means forpivotally connecting each pair of link-elements to adjacent pairs oflink-elements of the same form and and aligned with said slots only whensaid linkage is in 10 an extremely extended position, and wherein saidhooked prongs are provided with an expanded portion at the roots of saidlateral hooks thereon, said expanded portion having a diagonal diametergreater than the width of said slots but less than the length of saidslots, whereby said adjacent pairs of link-elements may be disengagedonly by tilting the outer link-element away from the inner link-elementwhen said link-elements are in an extremely 5 extended position.

References Cited in the file of this patent UNITED STATES PATENTS2,225,745 Kestenman Dec. 24, 1940 FOREIGN PATENTS 548,231 Italy Sept.20, 1956 324,396 Switzerland Sept. 15, 1957

